Tapiola gets a new flagship office in Tuultenristi
The Helsinki Metropolitan Area got a bold new flagship office when YIT’s Tuultenristi was completed in a demanding location in Tapiola, Espoo. The close cooperation between the contractor YIT and Sweco’ s structural designers played a key role in the successful project. We also provided LEED consultation, EU taxonomy compliance guidance and CRREM analyses for the project.
The Tuultenristi office was completed next to the Ainoa shopping centre in Tapiola, Espoo, in summer 2023. The project, which is unique for its district, is the first part of YIT’s hybrid block, which will also include a parking facility and apartments for approximately 700 Espoo residents.
“The Helsinki Metropolitan Area received a flagship from Tuultenristi, which is currently the newest and most modern office building in Tapiola,” says Taru Yliluoma, Project Manager at YIT. The property has already aroused spontaneous admiration among its users with its views and brightness, among other things.
Tuultenristi has been implemented in accordance with YIT’s Smart Building concept, so its adaptability, user-orientation and energy efficiency can be further developed during operation. The CO2 emission level of the site was determined at the beginning of construction and monitored throughout the project. The office has been awarded LEED Gold environmental certification.
The office was designed on top of a busy road
When Sweco started implementing Tuultenristi in summer 2021, there was just over a year to refine the structural solutions. The five-storey new building was designed at the busiest traffic hub on top of the existing yard deck.
“The project was identified as demanding from the very beginning, but luckily we had a really good team involved. Its two star players were definitely architects and structural designers,” Yliluoma says. He felt that the role of structural designer was above average because the schedule was so tight. However, Sweco’s structural engineers did not need to be rushed. “They knew what was expected of them at all times and delivered the plans at the right time.”
According to the building inspector and the city, the load transfer solution was so challenging that a third-party inspection was required for the plans. “The vertical loads of the office were transferred to the vertical pillars of the deck with a post-tensioned grate beam,” says Christoffer Enberg, Project Manager for structural engineering at Sweco. The building had to be designed at the same height as the deck and Merituulentori, because otherwise the office would not have become accessible. “The low level of interest rates made it difficult, for example, to plan hydro and heat insulation.”
The deck has only been stiffened in the east-west direction, so the staircase and elevator shaft at the southern end of Tuultenristi had to be extended from the other end of the deck all the way to ground level. “The shaft was built on a massive pile slab attached to the flood line and the watertight sheet pile wall of the West Metro tunnel,” Enberg says.
Safety limited lifts and element sizes
The structural designers and the contractor went through the installation plans together with particular care, because the deck crossing the six-lane road had to withstand a possible fall of the element.
“We carefully simulated that the deck can withstand the push forces sufficiently and that lifting can be carried out safely on a tight plot even on windy days,” says Enberg. Lifting routes and heights were restricted to ensure safe movement of elements over sufficiently long distances. In addition, the size of the elements was limited to half of the normal, about 5 tons.
Safety was also evident in the façade cladding. On the two lowest floors, in addition to aluminum sheets, there are massive ceramic tiles, which were attached to lightweight façade elements. “The secure fastening was checked several times during both design and construction,” says Enberg.
Tuultenristi, a takt production, was completed according to plan in about a year. Next, the project will continue with the construction of a car park and apartment buildings involving structural, HVAC and electrical designers from Sweco.
Photo: Arco/YIT